The present invention relates to a method for forming a lens at an end portion of an optical apparatus, a light transmission apparatus having a plurality of lenses at its end portion for transmitting a light and an optical information processing apparatus including a lens array at its end portion for processing an optical information.
In the first place, conventionally, there has been known a system in which a laser beam printer is used for forming an electrostatic latent image on a photosensitive medium.
Such a laser printer is provided with, for example, an optical scanning device. This device is provided with a cylindrical rotary head and an optical fiber array disposed adjacent to the rotary head.
Then, a light source is disposed at a position of the peripheral edge portion of the aforementioned rotary head. A motor is connected to the rotary head. When the rotary head is rotated by means of the motor, a light emitted from the light source is incident at its input end of the optical fiber array in order and is then emitted from its output end.
In this case, since a light emitted from the output end diffuses or spreads, two light spots adjacent to each other are superimposed, so that a clear image cannot be formed on a photosensitive drum.
In the next place, conventionally, since an optical signal transmission means of a printer, a copy machine or the like is provided with an optical fiber, a SELFOC lens, a laser light source and so on. The SELFOC lens is one of the gradient index lenses. In the optical fiber, an inputted light can be outputted at the other end after passing through the optical fiber. However, since the light diffuses in the air at the distal end of the optical fiber, a record medium must be placed close to the distal end of the optical fiber when the exposure on a photosensitive medium carried out by the optical fiber is performed. In the SELFOC lens array, a plurality of lenses are arranged within a solid resin, so that the outputted light focuses at a certain distance. However, since the light inputted into one SELFOC lens is very little in comparison with the amount of light emitted from a light source which provides an optical information, a transmission efficiency in a light intensity is very low. A laser light is a good means as the light transmission means except costs and maintenance of a light source and the control device thereof.
In the case that a fiber optical CRT having the optical fibers in front of the CRT is used as the light transmission means for providing an image information on the photosensitive recording medium, an electric signal of an image information is fed to the CRT in the form of an electron beam so as to pass through a Braun tube. Then, a fluorescent material applied to the front surface of the CRT is irradiated with a light beam so as to emit a light. Thereupon, the optical fibers are disposed in front of the CRT and the image information is outputted from the distal ends of the optical fibers. The fiber optic CRT is adapted to record the image information from the back surface of the photosensitive recording medium, namely in contact with a base member to which the photosensitive substance is applied. However, since a light outputted from the optical fiber diffuses throughout the medium, the light diffuses corresponding to a thickness of the base member of the photosensitive recording medium, so that the intensity of a light reaching the photosensitive substance lowers. Therefore, an image thus obtained becomes unclear.
Further, conventionally, in the case of a copy machine employing, for example, an LED array and the SELFOC lens as an optical information processing apparatus, an information is supplied as an electric signal to the LED array so that the LED can emit a light according to the electric signal. The photosensitive material is exposed by a light from the light-emitting portion through the SELFOC lens as a refractive index distribution type rod lens. A photosensitive component material such as selenium, silver salt, dry silver and the like is applied to the photosensitive material so that the information can be recorded in respective manners or modes according to the information to be recorded. The aforementioned LED array is composed of a large number of small light-emitting portions arranged in a line on a substrate having a plurality of electrodes.
In the case of the optical information processing apparatus employing the optical fibers as the optical signal transmission apparatus, the photosensitive material is exposed by a light from a light emission member through the optical fibers.
There is, however, the following problem associated with the aforementioned copy machine. That is, since a large occupied space is required for the copy machine because of a length of the SELFOC lens as an image throwing lens, the overall apparatus becomes large corresponding to the length thereof.
When the optical fibers are employed, there is the following problem. That is, since a light emitted from the optical fiber diffuses throughout a medium, the light spreads over the thickness of a base member of the photosensitive medium so that the intensity of the light reaching the photosensitive medium is lowered and an image thus obtained is dim.
It is an object of this invention to provide a method for forming at an end portion of an optical apparatus which is low in cost and high in productivity and which can provide a clear image by forming a lens at the distal end of an optical fiber.
It is another object of this invention to provide a optical signal transmission apparatus in which an outputted light having an optical information can reach a photosensitive substance from the distal ends of optical fibers of a fiber optic CRT without diffusing in a certain medium.
It is still another object to provide a clear image by condensing a light through a microlens provided for a light emission member thereof and make the overall apparatus smaller in dimension.